How to respond when someone is stuck in the past

It is a feature of dementia that they "time travel" and think that they are in their past. What is happening is that their brain if filling in the gaps caused by short-term memory loss with things from their past, so it feels to them that these things are recent. My mum used to tell me about something that had happened 20 or 30 years previously, but say it had happened "just this morning" - like telling me that she had seen her husband go off to work "just this morning" when in reality he had died 30 years previously.

I quickly learned that trying to bring her back to the present, or correct her, just caused distress. If she wasnt worried by this time-travelling, then I just used to make neutral noises. The problem was if she was upset by it. For example, if her husband (who she had seen "just this morning") hadnt come home from work and she was worried, or thought he was having an affair. It was useless to try and persuade her that he had actually died and I only did it once as it made her so distressed. So I used "love lies" and told her that he was working late that day and then tried to change the subject. Fortunately, as long as I could come up with a "solution" which calmed her fears, she would forget about it quite quickly.